what types of proxy data do scientists use to reconstruct pre-historic climates?

ice cores

tree rings

speleothems

what about deep sea sediment cores informs us about past glacial periods?

d18O of deep-dwelling foraminifera shells records ice volume

the cenozoic is the geologic eon corresponding to the past 65 million years. how do we know the timing of the events that punctuated such a period?

principle of superposition

radiometric dating with long-lived nuclides

overall, what happens to the oxygen isotopic composition of the deep ocean over the cenozoic?

it gets more positive

it gets heavier

why does the oxygen isotopic composition of the ocean change during the cenozoic?

the lighter isotope 16O is preferentially evaporated from the ocean and stored on land in glaciers, causing the ocean to become isotopically heavier

during which period was the antarctic continent ice-free?

paleocene-eocene thermal maximum

the paleocene-eocene thermal max happened approximately

55mya

what are glaciers?

accumulations of snow on land, turning into ice over time

where can we find glaciers today?

mountains

valleys

poles

what do ice cores record about climate?

temperature of snow formation

atmospheric composition

what do antarctic ice cores teach us about climate and CO2?

temperature and CO2 have gone hand-in-hand for the past ~800k yrs

oscillations in global ice volume. pattern: a slow gradual, descent into cold conditions, and an abrupt return to warm conditions. what do we call such warming episodes?

glacial terminations

over the past million years or so, what was the average spacing between ice ages?

~100k yrs

according to milankovitch theory, what is the pacemaker of the ice ages?

the insolation received at 65N during summer

what determines the average yearly insolation received by a point on earth?

precession

obliquity

eccentricity

when did the last glacial max occur?

20,000 yrs ago

at the last glacial maximum, a large ice sheet covered much of north america, in particular the northern half of the USA and canada. what was it named?

Laurentide ice sheet

in his AGU lecture, Dr Richard Alley calls CO2 "the biggest control knob" because

it seems to be explaining a large part of global temperature change

did the last glaciation happen smoothly?

no, it was marked by some abrupt cold reversal around 13kya

what defines abrupt climate change?

faster than the responsible forcing

too fast for living systems to adapt

2 examples of abrupt climate change

Younger Dryas

Dansgaard-Oeschger events

what processes matter for abrupt climate change?

destabilization of the methane clathrates

weakening of the thermohaline circulation by freshening

melting permafrost

what physical notion can help explain the abrupt nature of certain climate events?

tipping points

climate reconstructions of the past millennium are

quantitative proxy estimates based on a network of well-dated proxy records

which of the following climate events happened in the last millennium?
Little ice age
younger dryas
last glacial max

little ice age

what is the hockey stick controversy about?

whether the current global warmth is unprecedented in the past millenium

amongst the following civilization collapses, which was unlikely to be related to climate change?
Anasazi
Romans
Akkadians

Romans

the anasazi indians lived in the US southwest, a region presently marginal for agriculture. archeological records indicate that their population peaked around 1100AD, but that their main center was abandoned around 1170AD. what is a likely explanation?

the population peaked before the most severe megadrought of the millennium

what lesson can we derive from the climate-induced collapse of past civilizations?

even advanced societies can break down if climate change overcomes their resilience